Reversible ratchet cam slot drawout mechanism for switchgears



Feb. 15, 1955 w. J. DONALDSON 2,702,324 REVERSIBLE RATCHET CAM SLOT DRAWOUT MECHANISM FOR SWITCHGEARS Filed Aug. 1, 1951 3 Sheets-Sheet l r 17;.- J 2,43 J I L a Inventor:

Warf-en .J. Donaldson,

His AttoPne Feb. 15, 1955 Filed Aug. 1 1951 J DONALDSON W. REVERSIBLE. RA

TCHET CAM SLOT DRAWOUT MECHANISM FOR SWITCHGEARS 3 Sheets-Sheet 2 lnvehtor-z Warren J. bonaiqlson,

His A-t t-ohneg Feb. 15, 1955 w. J. DONALDSON 2,702,324

REVERSIBLE RATCHET CAM SLOT DRAWOUT MECHANISM FOR SWITCHGEARS Filed Aug. 1, 1951 3 Sheets-Sheet 3 Inventor Warren J. Donaldson by H is Attorney.

United States Patent REVERSIBLE RATCHET (1AM SLOT DRAWOUT MECHANISM FOR SWITCHGEARS Warren J. Donaldson, Upper Darby, Pa., assignor to General Electric Company, a corporation of New York Application August 1, 1951, Serial No. 239,706

15 Claims. (Cl. 200-50) The invention relates to metal-enclosed drawout switchgear and the principle object is to provide improved force amplifying manually operable insert and drawout, lock and interlock mechanisms particularly suitable for an automatic circuit breaker mounted on a carriage to form a completely removable switchgear unit that is provided with disconnect contacts whereby the breaker is connected to and disconnected from the circuit by insertion and withdrawal movement of the unit in a suitable metal enclosing unit or cubicle having cooperating circuit terminal contacts.

Another object is to provide an improved oscillating lever-operated automatically reversible pawl-and-ratchet involute slotted cam mechanism capable of compact side mounting between the removable unit and the cubicle and of obtaining the powerful mechanical advantage necessary for an operator to engage and disengage the disconnect contacts of a relatively large circuit breaker by effecting progressive movement of the unit both to and from the connected position upon oscillation of the operating lever, and also capable of securely locking the unit with the circuit breaker in the connected position.

Another object is to provide improved cooperating interlocking means for insuring that the circuit breaker is always tripped before the automatically reversible pawl can engage the ratchet to produce either the insertion or withdrawal movement of the unit.

Another object is to provide an improved manually operable oscillating lever type of drawout and interlocking mechanism that can readily be operated from the front of the unit or cubicle and requires only a very narrow mounting space between the sides of the enclosing cubicle and the sides of the switchgear unit on which the essential cooperating parts can be mounted with the rotatable involute cam and oscillatable lever either on the unit or on the cubicle as desired.

In the preferred form of the invention, a pair of rotatable disk-like slotted cam members are mounted on opposite sides of the removable switchgear unit and interconnected for joint rotation by means of a shaft extending across the back of the unit in order to produce balanced drawout and insert forces. Each cam member projects from the back of the unit and has an open end involute cam slot formed therein to engage with a cooperating camming pin fixed inside the cubicle. This improved camming construction enables a relatively long and powerful operating lever to be mounted coaxially adjacent one of the jointly rotatable cam members so as to extend from the back to be readily accessible for operation at the front of the switchgear unit. The long lever operates a reversible pawl to successively engage with two-way ratchet elements preferably formed on the periphery of the adjacent rotary cam member to efiect progressive rotation thereof in either direction upon oscillation of the operating lever and means are provided for automatically reversing the pawl at the end of rotation in each direction. Thus, even a large circuit breaker unit having strong spring pressed disconnect contacts of large current carrying capacity, such as to require a very large force to eifect engagement and disengagement pawl-and-ratchet mechanism, in conjunction with the final increased force multiplying camming action of the involute cam slot formed in the rotatable cam member. Furthermore, the improved involute cam slot and pin combination will inherently mechanically lock the unit in its connected position with the pin engaged with the inner end of the involute cam slot when made substantially tangential to the axis of the rotatable cam member, thus eflectively insuring against any accidental movement of the unit from its inserted or connected position.

In addition, the necessary interlocking for preventing insertion or withdrawal movement of the unit while the circuit breaker is closed is accomplished by providing a blocking member that is movable to the blocking position upon closure of the circuit breaker for preventing operative engagement of the pawl with the ratchet member. This blocking member cooperates with the pawl reversing means to completely free the pawl to prevent a withdrawal operation when the circuit breaker is closed and also renders it ineffective to produce an insert operation until the circuit breaker is opened.

Further objects and advantages of the invention will appear in the following description of the accompanying drawings, in which Fig. 1 is a side view of a removable circuit breaker unit enclosed in a metal-clad cubicle with one side of the cubicle almost completely removed in order more clearly to show the detailed structure and arrangement of the preferred form of the reversible ratchet cam drawout and interlock mechanism of the present invention. Fig. 2 is an enlarged view of the interlock mechanism that locks the door of the cubicle closed when the circuit breaker unit is in its normal operating connected position as shown in Fig. 1 and the circuit breaker is closed. Fig. 3 is a partial sectional view on the line 33 of the interlock mechanism shown in Fig. 2. Figs. 4, 5 and 6 are schematic side views showing the relative positions of the various operating parts as the circuit breaker unit is moved out of its enclosing cubicle.

Figs. 7 and 8 show a modification of the improved draw-' is shown as provided with a main and arcing contact se-,

quential operating mechanism 15 of the improved type more fully described and claimed in the patent application Serial No. 137,411, new Patent No. 2,581,181, filed January 7, 1950, by John A. Favre and assigned to the assignee of the present invention. This circuit breaker mechanism is of the overload current responsive trip-free multiple-toggle type so that the circuit breaker may be closed by an energy-storing motor-operated mechanism 16 of the improved type more fully described and claimed in the patent application Serial No. 196,075, now Patent No. 2,667,076, filed November 16, 1950, by John A.

Favre and assigned to the assignee of the present invention. In addition to the usual automatic overload cur,- rent responsive trip, the circuit breaker mechanism 15 also is provided with the separate manual and safety interlock trip pin 19.

The enclosing cubicle 20 for the circuit breaker unit 10 is provided with a vertically hinged door 21 having a manually operable catch 22, that will engage behind the inturned edge of the side of the cubicle 20 that is not shown but entirely removed in Fig. 1, so as to reveal all of the parts in cooperating relation inside the cubicle. Thus, it will be understood that the several rollers 24 that support the carriage 11 of the circuit breaker unit 10 are in fact supported by a channel mounted on the side of the cubicle that is removed. Likewise, the manually operable push-button 25 that is mounted on the slidable rod 26 is carried in the bracket 27 that is also mounted onthe removed side of cubicle 20. The rod 26 is operatively connected with the lever 27' to raise the link 28 and engage finger 29 with the circuit breaker trip e1etnent'19,

Patented Feb. 15, 1955,-

and thereby manually open the circuit breaker 14. The removedside .of cubicle 20.also.- carries the -pins .17 that slidably mount the interlock channel 17 having safety trip camming elements 31 and 32 with channel 17 interconnected with the door locking zlever .33 ;that .carries the Pin limo locking engagement with-the overhanging hook member. 35 when the door, 321: is closed.

tThe t ircuit breaker -;111'lit.i10 is provided .with an interlock .opearting lever 37 that is .pivotedatone end on the fixed pin ,38 with the other end of lever,37 slotted andv connected -by means of the pin ,39.so as to :rotate the lever 37 in the counterclockwise direction when thecircuihbreaker 14 is opened as shown in 'Eig. 1 and in the clockwise direction when the circuit breaker is closed. Thersliding link 40-is .mountedon:unit 10.and.operatively connected with the lever ,37 .at one ,end by means-of:the pin 41 ,and ;is tpr,ovided-at ,theother end with a locking finger 421that engages ina-notch ,43 formed in the transverselysliding channelqmember 17, so .as'to securelylock. the door 21in the. closed position when the circuit breaker is-plosed.

Theficircuit breaker t-removable. unit is provided with suitable disconnect contacts 50 that project from the back of the unit so as to be forcedinto firm circuit closing engagement withthe circuit-terminal contacts 51 that are mounted on the insulating supports 52 to extend through the back wall of the cubicle 20. As shown, the circuit terminal contacts 51 arecomposed of a plurality of resilient conducting fingers in annular socket form so asto becompressed togetherby meansof the encircling springs '53 andthereby establish a firm conducting pressure engagement between the circuit breaker disconnect contacts 50 and the circuit terminal contacts 51. This pressure engagement inherently results in. aconsiderable frictionalload that requires a materially increased force amplification inorder to enable manual operation of the removable circuit breaker-unit10 to and fromthe inserted or-connectedposition in which it is-shown in Fig.1.

In,accordance with thepresent.invention,,such increased forceamplification is obtained by means of the relatively long manual operating lever 55, the rotatable involute slotted member or disk'56, and the pawl and ratchet operating :connection between the lever and the cam, provided by the reversible pawl 57 and the seriesof twoway ratchet elements 58'formed on the periphery of the involute cam member 56. Intheprefer-red form shown, one end of lever 55 is'rotatably mounted on a shaft 60 that extends across the back of-the circuit breaker unit 10 and is rotatably supportedrin suitable. bearing'brackets secured'to the frame 12. Eachend of the shaft 60 carries an involute slotted cam member 56 fixed to the end of the shaft by the locking tongue 61'and suitable welding so that both of the cam members 56 always rotate jointly-in fixed angular relation on theshaft 60 to produce balanced camming forces. An involute cam slot 63 is formed in each cam member 56 to span the axis thereof and progressively amplify the camming force with-the inner end of theslot extending-tangentially with respect to the axis of shaft.60;so .as to engage with a pin 64 that is fixedly mounted-on the removed side of therenclosing casing .20. By means. ofthis involute cam construction, the removable switchgear unit 10 is securely locked in its inserted position with the disconnect contacts 50-held injfirm currentconducting engagement with the-circuitterminal contact 51 as shown in Fig. l. The outer end of the involutecam slot 63 isopen so asto disengage the pin 64 and thereby elfect thecomplete removal of the circuit breaker unit .10 from the enclosing casing 20.

"The manual operating handle 55 -is ,provided with a generally triangular shaped mounting plate 966 that is rotatably supported on the shaft 60 adjacent to the rotatable cam member 56, and the reversible pawl 57 v.is pivotally mounted adjacent one cornerof the triangularly shaped member 66 toengage with the coaxialseries of two-way ratchet elements ,58.formed on .theperiphery of the rotatable slottedmemberordisk 56. AsshOWH. the pawl 57 is mounted on pin 67 on. which the doubleaended centering spring "68 is coiled so ,that each endthereof may-engage with either pin 69 on thepawl or pin 70 on the member-66 to always biasthepawl57 and'the pins into alignment with the pin 67.

DRAWQUTQPERATION flIn order :to tidraw out :thecircuit breaker unit '10 from its insert or connected position inside the enclosing cubicle .20.as .shown in Fig. 1, the first requirement is-t0- trip the circuit breaker 14 in casevit is closed. Otherwise, as long as the circuit breaker 14 remains closed, the finger 42 on link 40 will engage the notch 43 and lock the door 21 in the closed position, thereby efiectively preventing access of an operator to the drawout operating handle 55. By pushingithepush button 25 to lift the finger29 carried by-link '2'8into engagement withthe trip'pin'19 the tripping of the circuit breaker operating mechanism 15 maybeeifected. When thecircuit breaker is opened as shown, the door catch 22 may beoperatedto openthe door so that the operator canthen apply force to lift the operating lever 55, which normally rests against the stop pin 70 on the breaker unit. Thus, upon lifting the lever 55, pawl 57 will engagetheend one in the series of two-way notching elements 58 formed on the periphery of the rotatable cam member 56, and thereby effect the first step in the joint rotation of both-'of-the cam members 56 in the clockwise direction. When the operating lever 55 is thus raised as far-as-thed0or.opening into the cubicle'20 per1nits, or as far as may be'convenient for the operator, a powerful camming force will be exertedtbythe involute cam 63 on the fixed pin "64 so-as to start-thedisengagement ofthe disconnect contacts 50 from the terminalzcont-actssl. T he locking latc'h 71 that is pivoted on the frame 12 is held in an inactive position as showndueto the engagement of the upper arm 72 of latch 71 with the pin 73 that is fixed onthe removed side wall of the cubicle 20. Upon lowering of the operating lever55, the pawl157 is returned to engage with a subsequent one of the two-way ratchet element 58 so thatby repeated lifting and lowering of thelever 55, cam member56 is progressively rotated in the clockwise direction. Thus, by the repeated pumping or oscillation of'the operating'lever55, the'rotatable cam 56 can ,be progressively rotated in the clockwise direction to cam the disconnect contact-50 entirely out of engagement with the terminal contacts 51 until the open end of the cam slot 63 is reachedas shown in Fig. 4. Thereupon, the carriage '11 maybe rolled out on the rollers 24 until the-carriage is stopped in the test position, :as shown intFig. 5, by a suitable releasable stop (not shown), wherein the trip pin 19 lies in the valley betweenthe tripping cams 31 and 32. :Thus, in the test position, the trip pin 19 dropsdown from'the cam 32 into the valley, and thus enables the circuit breaker mechanism to be closed and opened as desired-to inspect or test for proper operation, since the circuit breaker unit 10 is entirely disconnected from the circuit. The parts then occupy their relative positions shown in'Fig. '5, with the notched latch 71 in engagement with theipin 74 so as tohold the rotatable cam member '56 with .its open end in'proper aligned position for re-engagement with thefixed camming pin64. Upon release of the stop (not shown), 'the circuit breaker unit 10 then may be rolled out 'to its outermost extended position as shown in Fig. 6, from which it may be removed and, if desired, anotherunit substituted therefor.

During the withdrawal camming action, accidental rotation of the shaft 60 in either direction is effectively prevented bya springbrake member 76, which is pressed against the shaft 60 by'the compression springs77 to restrain rotation of the rotatable involute slotted member or 'disk '56 in-either direction uponv disengagement of the pawl 57. 'With the cam parts in their relative position shown inFig. 4, as soon as the-operating handle is released so as to restupon the stop pin 70, then the reversible pawl 57 is positioned opposite the pawl reversing notch or recess 78 that is formed in the periphery of the rotatable cam member 56 as shown.

Insert operation thereby automatically reversing pawl 57 in notch 78 so that the pawl can engage with the end two-way notching element 58 for operation in the insert direction. Thereupon a downward force exerted on the lever 55 will rotate the cam member 56 in the counterclockwise direction to produce a camming action between the involute cam slot 63 and the fixed pin 64 that will exert an amplified force sufficient to force the interengagement of the disconnect contacts 50 with the terminal contacts 51. By repeatedly pumping or oscillating the operating lever 55, a progressive rotation of the cam member 56 is obtained until the circuit breaker unit is returned to its fully connected position and the pawl 57 is automatically reversed by the open end of slot 63 and returned to the position in which it is shown in Fig. 1.

However, the circuit breaker must always remain opened until the door 21 of the cubicle is closed. This is due to the operation of the interlocks shown in Fig. 2, since the tension spring 80 will draw the sliding interlock channel 17 to the right and thereby maintain the cam element 32 under the circuit breaker tripping pin 19 and hold this pin in position to insure that the circuit breaker is tripped. Upon closing the door 21, the hooked bracket 35 will engage with pin 34 and thereby move the interlock link 17 to the left into its position in which it is shown in Fig. 1, wherein the closure of the breaker will elfectively lock the door closed and wherein the cam 32 is moved out from under the trip pin 19, so as to enable a closure of the breaker to be obtained.

In the modified form of drawout cam mechanism shown in Figs. 7 and 8, the rotatable cam member 56a is of somewhat ditferent configuration and the reversible pawl 57a is provided with a weighted end to produce the centering thereof. Furthermore, and more important, interlock means in the form of the pivoted member 85 is provided for preventing operative engagement of the pawl 57a with the series of peripheral two-way ratchet elements 58a while the circuit breaker is closed. To accomplish this, the pawl interlocking member 85 is pivotally supported on the frame 12 by the pin 86 and is arranged to be operated to the position in which it is shown in Fig. 7 by the pin 87 that is carried on the sliding link 40 to the position shown in Fig. 8 when the C11- cuit breaker 14 is closed.

Also as shown in Fig. 7, a modified form of latch mem ber 71a is pivotally mounted on the pin 90 extending from the frame 12 and carries a latching pin 91 into a cooperating notch 92 provided on cam member 56a so as to hold the rotatable cam member 56a in the pr edetermined position wherein the pin 64 that is fixed lnside the enclosing cubicle will engage with the open end of the involute cam slot 63a. The latch member 71a is provided with an integral cam surface 93 for engaging w1th the fixed pin 64 when the switchgear unit 10 is rolled into the enclosing cubicle 20 so as to raise the latch member 71a to its released position shown in Fig. 7 before the fixed pin 64 engages with the lip 94 formed at the open end of the involute slot 63a to stop the rolllng insert movement of the switchgear unit 10 with the fixed pin 64 in position to be engaged by the involute slot 63a upon clockwise rotation of the rotatable cam member 56a. However, the latch pin 91 still engages with the back wall 95 of the notch 92 so as to prevent any clockwise rotation of the cam member 56a.

A further feature of latch member 71a is its function to prevent handle 55 from being operated when unit 10 is cammed out to test position or beyond. At test position latch member 71a is disengaged from pin 64 permitting its fall to engage pin 91 with slot 92. In this position, notch 100 is in line with projection 101 on handle 55. Raising handle 55 will cause projection 101 to engage with notch 100 before reversible pawl 57a engages with first notch 58a on cam 5611. This prevents destructive forces from being applied to pawl 5711 while cam 56a is locked by pin 91.

Operation With the modified drawout parts in their respective positions shown in Fig. 7, the circuit breaker unit 10 is ready for camming to the connected position since the circuit breaker is open. If, however, the circuit breaker were closed, the interlock member 85 would be moved into its blocking position so as to tilt the pawl 57a to its inclined or tilted position as shown in Fig. 8. In such case, when the operating lever 55 is raised, the pawl 57d can only engage with the end two-way ratchet element 58 in such a manner as to continue rotation of the cam member 56a in the clockwise direction. However, such rotation will be effectively prevented by engagement of the latch pin 91 with the side wall 95. Upon return of the operating lever 55 into engagement with stop 70, the pawl 57a is returned to its tilted position in which it is shown in Fig. 8. In this way the interlock member 85 will effectively prevent any operative engagement of the pawl with the ratchet elements until the circuit breaker is opened.

Upon opening of the circuit breaker 14, the link 40 is lowered and carries the pin 87 to rotate the interlock member 85 to its inactive position as shown in Fig. 7, thereby freeing the Weighted pawl 57a to return to its upright position as shown. Consequently, when the operating lever 55 is now raised from the stop 70, pawl 57a is automatically reversed into its oppositely inclined position so as to enable the pawl to operatively engage with the end one of the series of two-way notching elements 58a in the direction to rotate the cam member 56a in the counterclockwise direction and thereby engage the involute slot 63a with pin 64 to cam the switch gear unit toward its insert or connected position. By repeated pumping or oscillation of operating lever 55, the successive two-way notch elements are engaged to progressively rotate the cam members 56a in the counterclockwise direction until the fixed pin 64 reaches the closed end of the involute slot with the switchgear unit in its final connected position. In this position when the handle is raised, the pawl is disengaged from the last one in the series of two-way notching elements and due to its weighted end returns to the upright position. Thus, when the operating lever 55 is returned into engagement with stop 70, the pawl 57a will occupy a less tilted position than that shown in Fig. 8 and will be biased to engage the end one of the two-way notching elements 58a to rotate the cam element 57a in the opposite direction.

But upon closure of the circuit breaker with the unit 10 in its final connected position as shown in Fig. 8, the interlock member 85 is moved to engage with the weighted end of the pawl 57a and thereby further tilt the pawl into the ineffective position in which it is shown in Fig. 8. Now, in case operating lever 55 is raised while the circuit breaker is thus closed, the pawl 57a is prevented from operative engagement with the end one of the two-way ratchet elements 58a. In this way, the interlock member 85 prevents operative engagement of the pawl with the ratchet elements until the circuit breaker is opened. When this occurs, the pawl can then be brought into operative engagement with the end to a ratchet element and the repeated pumping of the operating lever 55 will rotate the cam member 56a in the clockwise direction to cam the switchgear unit 10 out of its connected position.

The force amplification provided by the relatively long lever 55, the distance amplification provided by the ratchet 58a and reversible pawl 57a, and the further force amplifying action of the involute cam slot 63a enable the disconnect contacts 50 of the circuit breaker unit to be disengaged from the terminal contacts 51 inside the cubicle 20 with only a normal force applied to the end of the operating lever 55. As soon as the pin 64 reaches the open end of the involute slot, the switchgear unit can easily be rolled out of the cubicle. Thereupon, the latch pin 91 of the latch member 71:: is returned into locking engagement with the notch 92 in the rotatable carn member 56a so as to hold this member in the predetermined position required for re-engagement of pin 64 with the open end of the involute slot when the switchgear unit is reinserted in the cubicle.

In order to protect against any variation in the normal insert and withdrawal operation of the switchgear unit, as, for example, when an unskilled operator attempts to close the breaker when the unit is only half way inserted or withdrawn, a trip pin interlocking cam arrangement involving the earns 31 and 32 may be provided as shown in Fig. 1, if desired. However, it will be observed that in both the cam arrangement of Fig. 1 and the modified arrangement of Fig. 7, the insert operation is obtained by pushing down on the operating lever 55 with the upstroke idling, while the withdrawal operation is obtained by lifting up on the operating handle 55 with the downstrokeidling. ,In-eajchcasc, the cam is providedwith means for automatically reversing the pawl at the end of each insert or withdrawal operation, thereby automaticallycondition'ing the pawl to perform the reverse operation :uponsubsequent oscillation'of the operating lever 55.

It wilLbeapparent that, if desired, instead of :mounting the rotatable rinvolute cam and the oscillating lever and reversible pawl andratchet mechanism on the removable switchgear unit itself and the cooperating cam pins on the inside of the cubicle as shown and described, the respective mounting :of these ,parts may just as well be reversed with suitable rearrangement thereof to maintain the same principles rof cooperation 'therebetween. In the case of such reversalwin the mounting of the parts of the modified -form of the-invention shown in Figs. 7 and 8, a suitable separable ilinkage mechanism may be provided, partlyon the unit and partly on the cubicle, for effecting the movement of :the blocking member to prevent operative engagement of "the reversible 'pawl with theiratchet whenever the :circuit breaker :is closed with the :unit inits connected position and also ;in its disconneeted test position inside the cubicle. Thus the basic pawl blocking interlocking'principle remains the same.

What I claim .as new and desire to secure by Letters Patent of the United States is:

l. A movable carriage unit gforceramplifying operating mechanism having in combination a rotatable member provided with anropen' end :involute cam slot spanning the axis of the member and with a coaxial series of two-way ratchet elements, a cooperating member engageable with theqpposite-edges of'the involute'camslot'to move the unit in oppositedirections upon'correspondingrotation of i the rotatable member, a and an -;operating lever pivoted coaxially with the [rotatable membervand havingareverslble ,pawl for engaging the ratchet elements to rotate the'memberprogressively in=either direction upon oscillation of thelever.

2. A vmovablecarriage unit force-amplifying operating mechanism having in combination a centrally pivoted rotatable member provided with an open end involute cam .slot spanning the .axis .of the member and-with a coaxial series of :two-wayratchet elements, agcooperating member engageable with the involute-cam slot to move the unitreach way between two positions upon correspondingzrotation of thezrotatablermembenan oscillatable operating leverpivoted coaxially with.therotatable-memher and having a reversible pawl for successively engaging the ratchet'elements to rotate 1 the 1 member .;progr essively in either direction upon -;oscillation of.-the lever, and -means effective -in each position of" the .unit -for reversing the pawl in responseito pivotal 'movementof the opcrating lever.

3. A :removablecarriage ,unit force-amplifying operating-mechanismhaving in combination a rotatable-memher on the unit provided-with anopengendinvolute cam slot and with a series of peripheraltwo way ratchet elements, atfixed member-cngageable with the. open endof the! involute cam 1 slot: in 1 a predetermined. angular position of the-member to movethe unit-inronedirectionupon correspondingrotation rofv-the cam member and in the opposite direction upon reverserrotation of, the, cam memher, an ,oscillat-able-,operating;lever pivoted ,on-the unit coaxiallvadjacent-the rotatablegmember and having a reversible-pawl .forengaging the peripheral ratchet elements to rotate themernber progressively in either direction upon-oscillatiomofthe lever, andmeans including a latch biasedaupon r.emoval of the unit from thefixed member to'hold the.rotatzableimemberin the predetermined angular position onrthe unitandreleasable upon engagementof the ,fixedzmember witlrtheopen end of the .slot.

4. A removable carriage unit insert and drawout mechanism; having in, combination. a rotatable cam memberprovidedrwithvan involute cam slot. spanning the axis or saidrnemben-having thei-nner end thereof extending substantiallytangentially with respecttotheaxisof the rotatable member. andtheoutcr-endthereof open, a. cooperating member engaged withlthe innercnd of the involute ,cam slot to loekthe unit inrthefinsert position an'dto move'the unit upon rotation of the cammember between the insert and drawout position wherein the cooperating memberis-releasablefrom theopen end of the slot'tocffect removalcof the carriage -unit and an oscillatable operating 'lever pivoted coaxia'lly with the rotatable member andihavinga reversiblepawl-and ratchet onnec on with t e an more o rot te th mem r p ogres e n e h d r cti n up c l a 9 1 lever.

5. A removable carriage unit insert and drawout mechanism having in combination a pair of interconnected jointly rotatable disks spaced apart to receive the unit therebetween and each provided with an open end involute vearn slot spanning the axis of the disk, ,one of said disks .having a series of peripheral two-way ratchet elements, a pair of spaced apart SCOPQIB'tlllg members, each engageable with the involute earn slotlof a corresponding disk to move the unit upon joint rotation of the disks between the-insert andfdrawout position wherein each cooperating rmemberisreleasable from the open end of the correspondingslot to efiect removalof the unit, and 'antoscillatable operating lever ,pivoted coaxially with the one rotatable disk and ,having a reversible pawl for successively engaging the peripheral ,two-wayratchet elements of the one disk to rotate both cam disks progressivcly in either direction upon oscillation of the lever.

'6. In combination, a removable switchgear unit having disconnect contacts, a housing unit ,for the switchgear unit having disconnectcqntacts therein, a rotatable member on-one of the-unitshaving an open end invol utecam slot formed therein, a pin mounted on-the therunit for releasably engaging the cam ;sl0t-to .eifect relative ,rnovemer t of the unit ;in opp osit e directions upon corresponding rotation of the member-to engage anddisengage the disconnect contacts inside the housing, means including a reversible pawl and ratchet for rotating the member eachway, and meansrestraining rotation of the rotatable menllbel in e t direc ion 1 2 d se eme of the paw 7. In combination, aremovable switchgear unit having d c nnect con extendi r mth s th r a housing :for the -unit having circuit terminal contacts extending through the back ,thereof, a rotatable member extending fromthe backofthe unit and'having anopen end involute cam .slot formed therein, a pin mounted inside the housing-for engaging withthe open end of the cam slot to move the unit in opposite directions upon corresponding rotation of the member-t0 engage anddisengage the disconnect contaetswith the circuit terminal contacts inside the housing, ,and ,means rincluding a reversible pawl and ratchet mechanism; h aV-ing an operating lever -mounted coaxially adjacent the rotatable member and extending to the frontlof the unit for rotating the member, each way.

.8. :In combination, a removable switchgear unit having disconnect contacts, a rotatable member mounted on the unit and provided with a-series, of two-way ratchet elementsand with an ,invol-ute; carn ..-slot,sp,anning the axis of said member anrlghaving the inner'cnd thereof extending substantially ;tangentially with respect to .the axis r of 1 the f0tatab1 e;mmbr;nd the outer end thereof open, ajhousinghaving cooperating circuit terminal contacts'therein-and provided WithflffiXfii-illfifllbdl engaged Wiihgthfl inner end of the involute cam ,slot to lock the unit in the insert position with the disconnect contacts and cooperating circuit tot minabcontacts. in circuit closingrengagement andto-move therunit uponrotation of the cam, memben-betweenthe insert and drawout; position wherein'the fixed memberis releasable from-the open end of the ,slot to effect removal of ;the unit from the housing, and an oscillatable operating lever pivoted on the unit'coaxially with the rotatable member andph aving a reversible -pawl,f or successively engaging the ratchet elements to rotate .the,memberrprogres sively in either direction upon oscillation of the: lever.

,9. :ln'combination, a circuit breaker pnitghaving insert and drawout mechanism provided with reversible pawl and ratchetoperating means, andrinterlockrneans controlledby the circuit ;-breaker.for preventing operative engagement of, thepawl with the-ratchetwhen the circuit breaker is closed.

10. In combination, a metal cubicle having circuit terminal contacts therein a removable circuit breaker unit having disconnect contacts for engaging and disengaging the circuitterminal. contacts upon-reverse-movements of the element in the cubicle, laamember rotatably mounted on. oneside ofe-theunitrand havingran open .end involute cam: slot formed -therein and-provided .twith. peripheral two-way ratchetelements, a. pinextending from the corresponding ,side of the cubicle :for engaging the cam. slot toeifect the reverse. movements of the unit upon corresponding reverse rotation of the member, an oscillatable operating lever pivoted concentrically with the rotatable member and having a reversible pawl for successively engaging the ratchet elements to rotate the member progressively in either direction upon oscillation of the lever, and interlocking means for preventing operative engagement of the pawl with the ratchet when the circuit breaker is closed.

11. In combination, a metal cubicle having circuit terminal contacts therein, a removable circuit breaker unit having disconnect contacts for engaging and disengaging the circuit terminal contacts upon reverse movements of the unit inside the cubicle, a pair of interconnected cam members jointly rotatable on opposite sides of the unit and each having an open end involute cam slot formed therein and one of the members having peripheral two-way ratchet elements, latch means for holding the members in a predetermined angular position upon removal of the unit, a pin extending from the corresponding side of the cubicle for releasing the latch and engaging the open end of a corresponding cam slot in the predetermined angular position of the members upon reinsertion of the unit into the cubicle to elfect said reverse movements of the unit upon corresponding reverse rotation of the members, an oscillatable operating lever pivoted coaxially adjacent the one rotatable member and having a reversible pawl for successively engaging the peripheral two-way ratchet elements thereon to rotate the member progressively in either direction upon oscillation of the lever, and interlocking means including a blocking member movable upon closure of the circuit breaker for preventing operative engagement of the pawl with the ratchet.

12. A movable unit operating mechanism having in combination a centrally pivoted rotatable disk provided with an open end involute cam slot extending between diametrically opposed points on the disk and with a series of two way ratchet elements in the periphery of the disk, a cooperating member engageable with the pposite edges of the involute cam slot to move the unit in opposite directions upon corresponding rotation of the disk and an operating lever pivoted coaxially adjacent the disk and having a reversible pawl for engaging the peripheral ratchet elements to rotate the disk progressively in either direction upon oscillation of the lever.

13. A movable unit operating mechanism having in combination a rotatable member provided with an open end involute slot spanning the axis of the member and with a coaxial series of two way ratchet elements, a cooperating member engageable with the opposite edges of the involute cam slot to move the unit in opposite directrons upon corresponding rotation of the rotatable member, an operating lever pivoted coaxially adjacent the rotatable member and having a reversible pawl for engaging successive ratchet elements to rotate the member progressively in either direction upon oscillation of the lever, and means restraining rotation of the rotatable menliber in either direction upon disengagement of the paw 14. In combination, a removable unit having a member rotatably mounted thereon adjacent the inner side thereof and provided with an open end involute slot spanning the axis of the member and with a coaxial series of two way ratchet elements, a stationary member engageable with the opposite edges of the involute cam slot to move the unit in the insert and drawout directions upon corresponding rotation of the rotatable member, and an operating lever mounted on the unit coaxially adjacent the rotatable member to project for oscillation beyond the outer side of the unit and having a reversible pawl for engaging successive ratchet elements to rotate the member progressively in either direction upon oscillation of the lever.

15. A movable unit operating mechanism having, in combination, a rotatable member provided with a cam slot and with ratchet structure comprising a series of ratchet elements which extend between circumferentially spaced points on said rotatable member, a cooperating member engageable with said cam slot to move said unit each way between two positions upon corresponding rotation of the rotatable member, an oscillating operating lever pivoted coaxially with respect to said rotatable member and having a reversible pawl for successively engaging the ratchet elements to rotate the rotatable member progressively in either direction upon oscillation of the lever, and means effective in each of said two positions of the unit for reversing the pawl in response to pivotal movement of the operating lever, said means being characterized by the portion of said ratchet structure adjacent said circumferentially spaced points being recessed radially inwardly by an amount sufficient to permit reversing of sard pawl when said pawl is positioned opposite said recessed portion.

References Cited in the file of this patent UNITED STATES PATENTS 451,702 Sims May 5, 1891 2,258,150 Scott, Jr. Oct. 7, 1941 2,554,510 Spicer May 29, 1951 FOREIGN PATENTS 86,655 Sweden June 23, 1936 265,205 Italy May 31, 1929 

